The present invention is concerned with the simultaneous bulking and dyeing of linear polycarbonamide fibers.
The fibers with which the invention is concerned are silk-like linear, high molecular weight polyamide fibers in which at least 90% of the repeating units have the formula ##STR1## where S indicates a saturated cyclohexyl ring and the R substituents, which may be the same or different, are hydrogen and methyl. At least 40% by weight of the diamine constituent of the repeating unit is of the trans-trans (++) sterioisomeric configuration.
Fibers of the above type, and fabrics made therefrom, are described in U.S. Pat. No. 3,393,210, the subject matter of which is incorporated herein. Typically, the fibers are made from the polyamide polycondensate of 4,4'-diaminodicyclohexylmethane with dodecanedioic acid. Such material is commercially available depending on finish, denier, etc., as Nylon Types 470, 472, 473 trademarked as "Qiana" and available from the Textile Fibers Department of E. I. DuPont de Nemours & Co. (Inc.). The material has a silk-like handle, a density of 1.04, and a crystallinity similar to polyester fibers as reported by A. Liddiard, Review of Progress in Coloration, Vol. 1, page 64, June '67-September '69.
It is disclosed in DuPont's bulletin on Preparation, Dyeing and Finishing Woven and Warp Knit Fabrics of Type 470, Type 472, and/or T-473 Nylon Filament Yarns, that these fabrics can be thermally bulked and stabilized in the greige state or after being scoured and dried, either on an externally taperable pin tenter frame, or on a rotational hot roll contact unit, or similar type machines. It is clearly stated in the instructions for finishing such nylons that the fabrics must be thermally bulked and heat set before dyeing for beck and beam dyeing or thermally bulked and heat-set after dyeing for jig dyeing. However, heat bulking as such tends to yellow the "Qiana", renders it more difficult to dye, and does not help develop the silk-like handle of the fabric to its fullest degree.
My earlier application in Ireland, Ser. No. 2816/76 filed Dec. 22, 1976, available to the public on Aug. 20, 1977, describes a process for premanently bulking and stabilizing linear polycarbonamide fibers of the Qiana type, as well as developing the silk-like handle thereof, in which the fabric is treated with a solution or emulsion of an alcohol, washed and dried in order to bulk such fibers. To my knowledge, the art has not described a process wherein nylon Type 470, 472 or 473 fibers are chemically bulked and dyed at the same time. Also prior to my invention as herein described, it has been impossible to obtain deep bright dyeings of Qiana-type fabrics using the cationic-type (basic) dyes and using the process it is now possible to dye with cationic dyes and achieve strong, brilliant and fluorescent colorings on Qiana-type fabrics.
The principal object of the present invention is to provide a process for the simultaneous bulking and dyeing of fabrics made from fibers of the type indicated above (Type 470, Type 472 and/or Type 473 Nylon filament yarn "Qiana") which obviates prior art problems and positively develops the silk-like handle of these fabrics to their fullest degree while at the same time dyeing the fabrics.
These and other objects will also be apparent from the following more detailed description of the invention.